Reflective and transflective liquid crystal displays (LCDs) have been widely used in personal information display for its low power consumption and light weight. In most reflective and transflective direct-view display devices, a broadband quarter-wave retardation film is needed in order to obtain a good dark state. As shown in FIG. 1, the conventional broadband quarter-wave film laminates a chromatic half-wave film and a chromatic quarter-wave film at specific angles. See for example, S. Pancharatnam, Proceedings of the Indian Academy of Science, Section A, Vol. 41, p.130, (1955); and T. H Yoon, G. D. Lee and J. C. Kim, Opt. Lett., Vol.25(20), p. 1547, (2000). The fabrication processes of the prior art are relatively simple, however, its spectral bandwidth is insufficient.
There is a need to improve broadband technology to meet the intended purpose of making displays and delivery of personal information more effective. The broadband quarter-wave film of the present invention can be used in personal information tools and would further increase the contrast ratio and also serve as a reflective LCD when the twisted film is replaced by a liquid crystal cell.